The effect of bio-glass (45S5) addition on the physical properties of Mg-5Zn matrix composite has been investigated. Powder metallurgy method was used to fabricate the composite by mixing, compacting and followed by sintering. Mg-5 wt% Zn was reinforced with 5, 10, 15, 20, 25, and 30 wt% of bio-glass (BG). The physical properties such as density and porosity were determined using a pcynometer. Corrosion resistance was studied by immersion test. The results showed that porosity of the sintered sample decreased for the Mg-5 wt% Zn reinforced with 5 wt% of bio-glass. However, above 5 wt% of bio-glass, the porosity increased. The result also showed that corrosion resistance of Mg-5 wt% Zn increased as the amount of bio-glass increased.